Fire damper

ABSTRACT

A fire damper for an air distribution system includes a body defining a flow path and a closure means adapted to close the flow path when a temperature within the flow path exceeds a predetermined maximum temperature. A first flange is fixed to the body and a mounting means comprising a second flange is slidably engageable with and removable from the body. The mounting means comprises securing means for securing the mounting means to the body such that a building element through which the fire damper extends, in use, can be clamped between the first and second flanges. A flexible insulating sleeve configured for use with a fire damper, and a method of installing a fire damper, are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims is a continuation of U.S. Non-Provisionalapplication Ser. No., 16/416,497, filed May 20, 2019, which claimspriority to and the benefit of New Zealand Provisional PatentApplication Number 742724, filed May 21, 2018, the disclosure of whichare hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to a fire damper for impeding the spreadof fire and smoke through a cavity in a wall or floor which has beenformed for air flow, in particular HVAC air flow.

BACKGROUND

Combination smoke and fire dampers are used in buildings to aid inpreventing the spread of fire and smoke in the event of a fire in thebuilding. For simplicity such dampers are referred to herein as “firedampers”.

Fire dampers are a form of passive fire protection and are usuallyassociated with an air distribution system, for example an airconditioning system. Ducts, holes or passageways are adapted to allowair to flow through walls, partitions or floors. These are required tobe equipped with a fire damper that meets the fire rating standard setby a relevant building code. The damper is usually designed to shut orblock the passage during a fire in order to prevent the spread of smokeand/or fire.

Fire dampers may be configured to impede the spread of fire and heatwithin building compartments whilst maintaining the integrity of thebuilding element (most commonly a wall) through which the damper passesin use.

Current forms of fire dampers may be installed with high temperatureinsulation wool, for example Kaowool®, wrapped around the outside of thebody of the damper. The insulation is resistant to high temperatures andis used to insulate the internal cavity of the building element from theexternal surface of the fire damper so that heat from within the airdistribution system is not conducted to the wall during a fire.

Because the damper is very difficult to install with the insulation inplace, one damper of the prior art utilises a flanged steel sleevearound the insulation. However, since the steel sleeve conducts heatfrom the room bordered by the wall, this design relies on the cavitywithin the wall being air-tight in order to prevent the internal wallstructure from heating up and catching fire. This is disadvantageous, asit is difficult to ensure that the cavity remains air-tight,particularly if other apertures are made in the walls (for example forservices such as plumbing or electrical).

Another form of fire damper is provided with a ceramic sleeve toinsulate the fire damper. However, a disadvantage of this is that theceramic is a brittle material and can sometimes be damaged if nothandled correctly. If the fire damper is accidentally dropped prior toinstallation the ceramic sleeve may break. This means the fire damperneeds to be transported and installed carefully to avoid damage.

Another disadvantage of current fire dampers is that they may bedifficult or time consuming to install. The installation process mayrequire specialized tools and/or knowledge. It is important that firedampers are installed correctly as they may not function as required ifinstalled incorrectly. In addition, fire dampers which are mounted tothe wall by means of fasteners extending into the face of the wall mayrequire a relatively large outer flange, which may mean that the dampermust be mounted further from the ceiling of the building than isoptimum.

SUMMARY

According to some implementations of the present disclosure, a firedamper for an air distribution system comprises a body defining a flowpath; a closure means adapted to close the flow path when a temperaturewithin the flow path exceeds a predetermined maximum temperature; afirst flange which is fixed to the body; and a mounting means comprisinga second flange which is slidably engageable with and removable from thebody. The mounting means includes securing means for securing themounting means to the body such that a building element through whichthe fire damper extends, in use, can be clamped between the first andsecond flanges.

The above summary is not intended to represent each embodiment or everyaspect of the present invention. Additional features and benefits of thepresent invention are apparent from the detailed description and figuresset forth below.

BRIEF DESCRIPTION OF DRAWINGS

Further aspects of the present disclosure will become apparent from thefollowing description which is given by way of example only and withreference to the accompanying drawings in which:

FIG. 1 shows a side perspective view of a fire damper according to anembodiment of the present disclosure;

FIG. 2 shows a side view of the fire damper of FIGS. 1 ;

FIG. 3 shows a view of the fire damper of FIG. 1 from one end;

FIG. 4 shows an end view of the fire damper of FIG. 1 opposite to theend view shown in FIG. 3 ;

FIG. 5 shows a partial perspective view of one end of the fire damper ofFIG. 1 ;

FIG. 6 shows an enlarged view of detail A of FIG. 5 ;

FIG. 7 shows an exploded view of a fire damper of FIG. 1 ; and

FIG. 8 shows a cross-sectional side view of the fire damper of FIG. 1installed in a cavity in a wall.

DETAILED DESCRIPTION

The present disclosure describes an improved fire damper for impedingthe spread of fire in a building and provides certain desirableadvantages.

All references, including any patents or patent applications that may becited in this specification are hereby incorporated by reference. Noadmission is made that any reference constitutes prior art. Anydiscussion of the references states what their authors assert, and theapplicants reserve the right to challenge the accuracy and pertinency ofthe documents that may be cited. It will be clearly understood that,although a number of prior art publications may be referred to herein,this does not constitute an admission that they form part of the commongeneral knowledge in the art, in New Zealand or in any other country.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise”, “comprising”, and thelike, are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense, that is to say, in the sense of“including, but not limited to”.

Further aspects and advantages of the present disclosure of an improvedfire damper will become apparent from the ensuing description which isgiven by way of example only.

Referring first to FIGS. 1 to 4 , a fire damper for an air distributionsystem, for example an air conditioning system, is generally referencedby arrow 100.

The damper 100 comprises a body 1 which defines a flow path between aninlet 2 and an outlet 3. In preferred embodiments the body 1 issubstantially cylindrical, although in other embodiments the body 1 mayhave a non-circular transverse cross-section.

The damper 100 is provided with a closure means 4 which is adapted toclose or block the flow path when a temperature within the flow pathexceeds a first predetermined temperature, for example 70° C. In theembodiment shown the closure means 4 comprises a rotatably mounted plate5. The plate 5 is operatively connected to a biasing means, for examplea spring formation 6, which biases the plate 5 to the closed positionshown in FIGS. 1 to 7 . A suitable temperature dependent holding means 7is provided to hold the closure means 4 in an open position until thetemperature within the flow path exceeds the first predeterminedtemperature. In one embodiment the holding means 7 comprises a fusiblelink, such as is known to the art. In other embodiments of thedisclosure (not shown) an alternative closure means 4 and/or holdingmeans 7 may be provided.

Bimetallic Strip

Referring next to FIGS. 5 and 6 , in the embodiment shown the damper 100is provided with a locking means 8 for locking the rotatable plate 5 inthe closed position when the temperature within the flow path exceeds apredetermined maximum temperature. In the embodiment show the lockingmeans 8 comprises a bimetallic strip 9 which is mounted inside the body1 within the flow path. The bimetallic strip 9 may be configured to bendinward towards a centre of the flow path when the temperature within theflow path exceeds a second predetermined maximum temperature. The secondpredetermined maximum temperature is lower than the first predeterminedtemperature, and may be, for example 40° C. The bimetallic strip 9 ispreferably shaped and orientated such that the rotatable plate 5 canpass over the bimetallic strip 9 (possibly by deflecting the strip) whenthe holding means 7 releases the closure means 4 (i.e. stops resistingmovement to the closed position), thereby allowing the spring formation6 to move the plate 5 to the closed position. However, the bimetallicstrip 9 is configured and orientated to prevent movement of the plate 5away from the closed position for as long as the temperature within theflow path is greater than the second predetermined maximum temperature.When the temperature within the flow path is less than the secondpredetermined maximum temperature the bimetallic strip 9 is configuredto move to an initial position (shown in FIGS. 5 and 6 ) in which thestrip does not interfere with the movement of the closure means 4. Inthe embodiment shown the bimetallic strip 9 lies against an internalwall of the body 1 when in the initial position. In alternateembodiments (not shown), more than one bimetallic strip 9 may be used toprevent movement of the plate 5 away from the closed position. Thebimetallic strips may be located on opposite sides of the internal wall.The bimetallic strips may also be located such that they are positionedon opposite sides of the plate 5 when it is in the closed position.

In some embodiments the bimetallic strip 9 may have taper 10 on one sideto facilitate the plate 5 in moving to the closed position over thestrip. In some forms of the technology the bimetallic strip starts tobend inwards when the temperature within the flow path exceeds atemperature of approximately 40° C. However, the bimetallic strip 9 onlyreaches an effective position, (i.e. when the bimetallic strip isconfigured and orientated to prevent movement of the plate 5 away fromthe closed position) when temperature exceeds the predeterminedtemperature of the temperature dependent holding means 7.

Moveable Flange

Referring back to FIGS. 1 to 4 , and in particular FIG. 7 , a firstflange 11 is fixed to an exterior of the body 1. In the embodiment shownthe first flange 11 extends around the entire circumference of thecylindrical body 1. A plurality of spacers 12 may be provided adjacentthe first flange 11 to prevent contact between an exterior surface ofthe body 1 and an internal surface of an aperture in a building element(e.g. a wall, partition, floor or ceiling) through which the fire damper100 extends when in use. The spacers 12 are preferably spaced apartaround the circumference of the body 1. In preferred embodiments eachspacer 12 comprises a ramp portion 13 to assist with insertion of thedamper 100 and the spacers into the aperture.

The damper 100 is further provided with a mounting means 14 comprising asecond flange 15 connected to an annular base 16. The mounting means 14is slidable relative to the exterior of the body 1 and can be removedentirely from the body 1. The mounting means 14 is further provided withsecuring means 17 for securing the mounting means 14 to the body 1 whenin use.

In the embodiment shown the securing means 17 comprises at least onetongue 18, more preferably a plurality of tongues 18. Each tongue 18extends circumferentially, substantially parallel to the base 16 of themounting means 14, and is connected to the base 16. In preferredembodiments the tongue(s) 18 and the base 16 of the mounting means 14may be integrally formed. For example, in the embodiment shown eachtongue 18 is defined by a cutting a slot in the base 16 of the mountingmeans 14 to define the outer edge of the tongue 18.

The securing means 17 further comprises an adjustable ring 19 which isconfigured to extend around the tongue(s) 18 and to clamp the at leastone tongue 18 to an outer surface of the body 1. In a preferredembodiment the adjustable ring 19 comprises a hose clamp, for example aworm drive type hose clamp. The securing means 17 allows the mountingmeans 14 to be secured to the body 1 of the damper 100 at any requiredposition along the body 1 such that the second flange 15 can abut, inuse, an external surface of the building element to which the damper 100is mounted in use.

In preferred embodiments the base 16 of the mounting means 14 isprovided with at least one, more preferably a plurality of retainingmeans 20 for retaining the securing means 17 in position on the base 16of the mounting means 14. The retaining means 20 may comprise loopformations formed in the base 16.

In preferred embodiments one or more preferably both flanges 11, 15 maybe provided with an intumescent material 21 to create an improved sealagainst the building element when in use.

Flexible Sleeve

In preferred embodiments of the disclosure a flexible insulating sleeve22 is provided around the body 1 of the damper 100, when in use, andextends along a portion of the length of the body 1.

The insulating sleeve 22 acts as a heat shield and comprises a flexiblehigh temperature insulating material such as a refractory ceramic woolfibre provided within a flexible casing. In preferred embodiments theouter casing 23 comprises a metalized foil fibreglass fabric. Theflexible casing is preferably reflective so as to minimise radiant heatabsorption by the insulating material.

In preferred embodiments the insulating sleeve 22 is substantiallyring-shaped or annular. The insulating sleeve 22 preferably has aninside diameter which is greater than an outside diameter of the body 1of the damper 100 such that in use, the insulating sleeve 22 does nottouch the body 1 of the damper 100, or at least does not touch the body1 of the damper 100 around its entire circumference. In this wayconductive heat transfer from the body 1 of the damper 100 to theinsulating sleeve 22 is minimised.

In one embodiment the sleeve 22 (e.g. for use with a damper body havingan outside diameter of substantially 240 mm) has an inside diameter ofsubstantially 270 mm, and is substantially 30 mm thick and 100 mm long.

Installation

Referring next to FIG. 8 , a damper 100 of the present disclosure may beinstalled by the following method, described below with reference toinstallation through a wall of a building.

First, an aperture is created in the wall 30. The diameter of theaperture is preferably greater than an outside diameter of the body 1 ofthe damper 100, as provided in the relevant standards or codes.

Next, the insulating sleeve 22 may be inserted through the aperture intothe wall cavity 31. Since the sleeve 22 is flexible it may be deformedto reduce its diameter before insertion into the cavity, andsubsequently returned to its original shape once inside the cavity 31.

With the flexible sleeve 22 in position and the mounting means 14removed from the body 1 of the damper 100, the damper body 1 can beinserted into the aperture. With the damper body 1 in position, themounting means 14 can be reinstalled onto the body 1 such that thesecond flange 15 (or the intumescent material 21 attached to the secondflange 15) is in contact with the surface 32 of the building element tothereby clamp the wall 30 between the first and second flanges 11, 15.The securing means 17 can be used to hold the mounting means 14 inposition.

It will be appreciated that because some aspects of the presentlydisclosed damper are held in position by the clamping action of thefirst and second flanges 11, 15, rather than by fasteners extendingthrough the flanges and into the building element, the flanges may besmaller (i.e. of smaller diameter) than the flanges of the fire dampersof the prior art. This may mean that the fire damper 100 can beinstalled closer to a ceiling or floor than some dampers of the priorart.

It will also be recognised that although the damper 100 of the presentdisclosure provides good sealing against the surface of the buildingelement (e.g. wall), particularly when the flanges are provided with anintumescent material, the fire rated performance of the damper 100 isnot dependent on the flanges excluding oxygen from the cavity, and sothe damper 100 will perform to the required standard even if thebuilding element has other non-sealed penetrations (for example forplumbing or wiring).

The damper of the present disclosure may also be more robust than somedampers of the prior art, and may be easier and more convenient toinstall.

According to a one aspect of the present disclosure, there is provided aflexible insulating sleeve configured for use with a fire damper, thesleeve comprising a high temperature insulating wool provided within aflexible casing.

Preferably, the casing is formed from a flexible metallic tape.

Preferably the metallic tape comprises metalized foil fibreglass fabric.

Preferably, the insulating sleeve is substantially ring shaped.

Preferably the high temperature wool comprises refractory ceramic woolfibre.

According to another aspect of the present disclosure, there is provideda fire damper for an air distribution system, the fire dampercomprising: a body defining a flow path; a closure means adapted toclose the flow path when a temperature within the flow path exceeds apredetermined maximum temperature; a first flange which is fixed to thebody; and a mounting means comprising a second flange which is slidablyengageable with and removable from the body; wherein the mounting meanscomprises securing means for securing the mounting means to the bodysuch that a building element through which the fire damper extends, inuse, can be clamped between the first and second flanges.

Preferably the body is substantially cylindrical.

Preferably, the mounting means comprises an adjustable ring.

Preferably, the adjustable ring is in the form of a hose clamp.

Preferably, the mounting means comprises at least one tongue which isconfigured to be clamped by the adjustable ring to the body of the firedamper. More preferably the mounting means comprises a plurality of saidtongues.

Preferably the mounting means comprises at least one retaining means forretaining the adjustable ring.

Preferably, the first and second flanges are provided with anintumescent material on at least one face that abuts the buildingelement when in use.

Preferably the body is provided with a plurality of spacer meansadjacent the first flange, the spacer means spaced apart around thebody, wherein the spacer means are configured to prevent contact betweenthe body and an internal surface of an aperture in the building elementthrough which the fire damper extends.

Preferably each spacer means comprises a ramp portion.

Preferably, a surface of the mounting means which faces the body of thefire damper is provided with an intumescent material.

Preferably, the fire damper comprises at least one locking means forlocking the closure means in a closed configuration when the temperaturewithin the flow path exceeds the predetermined maximum temperature.

Preferably, the or each locking means comprises a bimetallic strip.

Preferably, the fire damper is provided with the flexible insulatingsleeve of the first aspect, wherein, in use, the flexible insulatingsleeve is provided over the body and between the first and secondflanges.

According to yet another aspect of the present disclosure, there isprovided a fire damper for an air distribution system, the fire dampercomprising: a body defining a flow path; a closure means comprising arotatable plate, wherein the closure means is adapted to rotate theplate to a closed position when a temperature within the flow pathexceeds a predetermined maximum temperature, thereby closing the flowpath; at least one locking means mounted to an inner surface of the bodyof the fire damper, within the flow path; wherein the or each lockingmeans is configured to move to a locking configuration when atemperature within the flow path increases above a predeterminedtemperature, wherein, when in the locking configuration the lockingmeans is configured to allow the rotatable plate to close but preventsthe rotatable plate from reopening.

Preferably, the or each locking means can be reset to its originalconfiguration.

Preferably, the or each locking means automatically returns to itsoriginal configuration when the temperature decreases below thepredetermined temperature.

Preferably the or each locking means comprises a bimetallic stripconfigured to bend inwards to a locking position when a temperaturewithin the flow path increases above the second predeterminedtemperature.

Preferably the bimetallic strip is configured to returns to its originalconfiguration when the temperature decreases below the predeterminedtemperature.

Preferably, at least one side of the bimetallic strip is tapered toallow the rotatable plate to pass the bimetallic strip when moving tothe closed position.

Preferably, the bimetallic strip starts to bend inwards when thetemperature in the flow path is in the range 30° C.-40° C.

According to yet a further aspect of the present disclosure, there isprovided a fire damper for an air distribution system, the fire dampercomprising: a body defining a flow path; a first flange which is fixedto the body; a closure means comprising a rotatable plate, wherein theclosure means is adapted to rotate the plate to a closed position when atemperature within the flow path exceeds a predetermined maximumtemperature, thereby closing the flow path; a holding means adapted tomaintain the rotatable plate in an open position until the flow pathexceeds the predetermined maximum temperature; a flexible insulatingsleeve adapted to be positioned surrounding a portion of the body inuse, the sleeve comprising a high temperature wool provided within aflexible outer casing; a mounting means comprising a second flange whichis slidably engageable with and removable from the body; and at leastone bimetallic strip mounted to an inner surface of the body of the firedamper, within the flow path; wherein the mounting means comprisessecuring means for securing the mounting means to the body such that, inuse, a building element through which the fire damper extends can beclamped between the first and second flanges; wherein the or eachbimetallic strip is configured to bend inwards to a lockingconfiguration when a temperature within the flow path increases abovethe predetermined temperature, and wherein when in the lockingconfiguration the bimetallic strip is configured to allow the rotatableplate to close but prevents the rotatable plate from reopening.

Preferably, at least one spacer is provided adjacent the first flange tocreate space between the building element and the body of the damper andensure the body of the damper is centered.

Preferably, the spacer comprises a ramp portion.

Preferably, the damper comprises a plurality of spacers spaced apartaround the circumference of the body.

Preferably, the holding means comprises a fusible link.

Preferably, the fire damper comprises two bimetallic strips, wherein afirst of the bimetallic strips is located on a first side of therotatable plate and a second of the bimetallic strips is located on anopposite side of the rotatable plate.

According to further aspects of the present disclosure there is provideda method of installing a fire damper, such as in one of the aboveaspects, in a cavity in a building element, the method comprising thesteps of: inserting a flexible insulating sleeve within the cavity;inserting the body of the fire damper, with the mounting means removed,into the cavity through the insulating sleeve; positioning the firstflange of the fire damper to abut a first side of the building element;installing the mounting means onto the body and adjusting the mountingmeans such that the second flange abuts the second side of the buildingelement and the building element is clamped between the first and secondflanges.

Preferably the step of adjusting the mounting means comprises the stepof tightening a hose clamp to clamp at least one tongue of the flange tothe body of the fire damper.

Reference to any prior art in this specification is not, and should notbe taken as, an acknowledgement or any form of suggestion that thatprior art forms part of the common general knowledge in the field ofendeavour in any country in the world.

It is contemplated that some aspects of the presently disclosed devicesmay also be said broadly to be comprised in the parts, elements andfeatures referred to or indicated in the specification of theapplication, individually or collectively, in any or all combinations oftwo or more of said parts, elements or features.

Where in the foregoing description reference has been made to integersor components having known equivalents thereof, those integers areherein incorporated as if individually set forth.

It should be noted that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications may be madewithout departing from the spirit and scope of the invention and withoutdiminishing its attendant advantages. It is therefore intended that suchchanges and modifications be included within the present invention.

Aspects of the present invention have been described by way of exampleonly and it should be appreciated that modifications and additions maybe made thereto without departing from the scope thereof.

What is claims is:
 1. A flexible insulating sleeve configured tosurround a portion of a body of a fire damper in use, the sleevecomprising a high temperature insulating wool completely encased withina flexible casing.
 2. The flexible insulating sleeve of claim 1, whereinthe casing is formed from a flexible metallic tape.
 3. The flexibleinsulating sleeve of claim 2, wherein the metallic tape comprisesmetalized foil fibreglass fabric.
 4. The flexible insulating sleeve ofclaim 1, wherein the insulating sleeve is substantially ring shaped. 5.The flexible insulating sleeve of claim 1, wherein the high temperaturewool comprises refractory ceramic wool fibre.
 6. A fire damper for anair distribution system, the fire damper comprising: a body defining aflow path; a first flange which is fixed to the body; a closure meanscomprising a rotatable plate, wherein the closure means is adapted torotate the plate to a closed position when a temperature within the flowpath exceeds a predetermined maximum temperature, thereby closing theflow path; a holding means adapted to maintain the rotatable plate in anopen position until the flow path exceeds the predetermined maximumtemperature; and a flexible insulating sleeve according to claim 1surrounding a portion of the body.
 7. The fire damper of claim 6 furthercomprising a mounting means comprising a second flange which is slidablyengageable with and removable from the body, wherein the mounting meanscomprises securing means for securing the mounting means to the bodysuch that a building element through which the fire damper extends, inuse, can be clamped between the first and second flanges.
 8. The firedamper of claim 7, wherein the body is substantially cylindrical.
 9. Thefire damper of claim 7, wherein the mounting means comprises anadjustable ring.
 10. The fire damper of claim 7, wherein the first andsecond flanges are provided with an intumescent material on at least oneface that abuts the building element when in use.
 11. A method ofinstalling a fire damper according to claim 7 in a cavity in a buildingelement, the method comprising the steps of: i. inserting the flexibleinsulating sleeve within the cavity; ii. inserting the body of the firedamper, with the mounting means removed, into the cavity through theinsulating sleeve; iii. positioning the first flange of the fire damperto abut a first side of the building element; and iv. installing themounting means onto the body and adjusting the mounting means such thatthe second flange abuts a second side of the building element and thebuilding element is clamped between the first and second flanges. 12.The method of claim 11 wherein the step of adjusting the mounting meanscomprises the step of tightening a hose clamp to clamp at least onetongue of the flange to the body of the fire damper.